Lathces shape a rotating workpiece with a tool, for example, a nonrotating tool bit, boring bit, or similar cutting tool or cutter, which is exclusively moved in cooperating manner with respect to the workpiece by an advancing device i.e. the tool slide which can have a cross feed and can carry a tool post. Many machining operations, however, require an additional tool, such as a milling head or a drilling tool, for example. When shaping a shaft or similar workpiece, a groove intended for a key or the like therein can be produced by milling of the corresponding groove opening. This machining operation can be carried out after removing the workpiece from the lathe and by securing or chucking it in a milling machine.
In order to avoid such laborious exchanges or workpiece transfers, it has been suggested to provide so-called machining or production centers which allow a relatively universal machining of the desired workpiece configuration by lathe operation, as well as by milling and drilling. Recently, a machine tool of this type has been suggested which includes a toolhead arrangement for holding a desired tool and having tool retaining devices for cutters and a further device for rotating tools, such as, for example, milling heads and drilling spindles. The toolhead is swung or rotated for the tool exchange operation through an arc of 180.degree., and the tool in use is thereby swung away from the workpiece. Since the toolhead has two separate devices, one each respectively for a fixed tool and for a rotating tool, with each movement of the toolhead - i.e. during the tool exchange, as well as during longitudinal or planar movements with respect to one production position - care must be taken that collisions of parts of the machine or a part of the machine with the workpiece are avoided. When one assumes that the one tool retainer device is equipped with a cutter, or a tool holder and cutter, and the other tool retainer device is equipped with a drill rod of wide working range, it is clear that the latitude of the toolhead is considerably restricted. When one tool is removed, and the respective retainer is left empty, such retainer is prone to accumulate dirt, for example, turnings or similar chips, and the machine is liable to be disrupted in its functioning. Thus covers are necessary for the exposed parts.